Distributed cooling of arrayed semi-conductor radiation emitting devices

ABSTRACT

Techniques for the removal of waste heat from solid state, semiconductor devices (such as cooking or heating devices) are provided. In particular, techniques for conducting waste heat away from the device through a heat sink in contact with a cooling system are provided. In addition, a multi-head cooling system applicable to multiple solid state, semiconductor sources is provided.

This application is based on and claims priority to U.S. Provisional Application No. 61/350,352, filed Jun. 1, 2010, which is incorporated herein by reference in its entirety.

FIELD

The presently described embodiments relate, in general, to a novel system configuration(s) and associated methods for the removal of waste heat from solid state, semi-conductor array cooking systems and, in particular, to the conduction of the waste heat away from the devices array through a heat sink in contact with a cooling system. In addition, this application includes a design of a multi-head cooling system applicable to cool multiple solid state, semi-conductor array irradiation sources.

BACKGROUND

The advantages of heating and cooking with irradiation produced by arrays of semi-conductor devices have been well documented. For example, a prior patent, U.S. Pat. No. 7,425,296, discloses such advantages. Increased device lifetime, greater output energy control, improved energy efficiency, compact size and improved repeatability are all desirable characteristics in heating, curing, and cooking processes intended for residential, commercial or industrial applications. The efficiency and lifetime of these devices, however, is closely related to the ability to successfully remove the waste heat produced during the conversion of electricity to electromagnetic or other irradiation energy. Indeed, the primary failure mode of any semi-conductor devices is the damage that can occur during overheating.

Current cooling methodologies for semi-conductor of devices include metal heat sinks, forced air systems and closed and open pumped liquid heat exchanger systems. Metal heat sinks and forced air systems have the disadvantage of low cooling capacity, with the best possible temperature set at the local ambient temperature while pumped liquid systems require large reservoirs, bulky pumps and provide only low relative efficiency when maintaining the coolant temperature near or below ambient. The utility of vapor phase cooling for electronic circuit components and other power electronics that require removal of large amounts of waste heat have been around since the 1960s.

The previous systems deal primarily with the design and implementation of two-phase cooling circuits, with at least one going so far as to specify the use of the cooling system for solid state circuit components. In addition, two-phase systems that are current commercially available are typically sized for industrial applications with typical capacities in the 10s of kilowatts.

BRIEF DESCRIPTION

In one aspect of the presently described embodiments, the system comprises a mounting substrate to which the array of semi-conductor based radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features, a heat exchange body connected to a second surface of the mounting substrate, heat exchange fluid cavity within the heat exchange body operative to maintain a flow of heat exchange fluid in the heat exchange body, and, fluid connections provided to an inlet and an outlet of the heat exchange fluid cavity.

In another aspect of the presently described embodiments, the system comprises a cooling system connected to the fluid connections.

In another aspect of the presently described embodiments, the cooling system is at least one of a vapor phase cooling system, water-based cooling system, air based cooling system or refrigerant-based cooling system.

In another aspect of the presently described embodiments, the semi-conductor based radiation emitting devices emit energy in narrow band in one of the infrared, ultraviolet and visible ranges.

In another aspect of the presently described embodiments, the narrow band is less than 300 nm, full width half max.

In another aspect of the presently described embodiments, the semi-conductor based radiation emitting devices emit energy in the microwave range.

In another aspect of the presently described embodiments, the mounting substrate is formed of or contains at least one of copper material, diamond material, nano-conductor composite material or alloys thereof.

In another aspect of the presently described embodiments, the mounting substrate and the heat exchange body are integral.

In another aspect of the presently described embodiments, the system further comprises a controller operative to control a flow of fluid to the heat exchange fluid cavity.

In another aspect of the presently described embodiments, the system further comprises at least one of a fluid regulator and a temperature sensor.

In another aspect of the presently described embodiments, the array is two-dimensional.

In another aspect of the presently described embodiments, the array is an X-by-Y array wherein both X and Y are greater than 1.

In another aspect of the presently described embodiments, the system comprises a first array cooling subassembly including a first mounting substrate to which a first array of semi-conductor based radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features, a first heat exchange body connected to a second surface of the mounting substrate, a first heat exchange fluid cavity within the first heat exchange body operative to maintain a flow of heat exchange fluid in the first heat exchange body, and first fluid connections provided to an inlet and an outlet of the first heat exchange fluid cavity, and, a second array cooling subassembly including a second mounting substrate to which a second array of semi-conductor based radiation emitting devices is mounted on a first surface thereof, a second heat exchange body connected to a second surface of the mounting substrate, a second heat exchange fluid cavity within the second heat exchange body operative to maintain a flow of heat exchange fluid in the second heat exchange body, and second fluid connections provided to an inlet and an outlet of the second heat exchange fluid cavity.

In another aspect of the presently described embodiments, the system further comprises a cooling system connected to the first array cooling subassembly and the second array cooling subassembly.

In another aspect of the presently described embodiments, the first array cooling subassembly and the second array cooling subassembly are connected in parallel to the cooling system.

In another aspect of the presently described embodiments, the first array cooling subassembly and the second array cooling subassembly are connected in series with the cooling system.

In another aspect of the presently described embodiments, the first array cooling subassembly and the second array cooling subassembly are arranged relative to a work area to perform heating and cooking functions.

In another aspect of the presently described embodiments, the work area is an oven cavity.

In another aspect of the presently described embodiments, the work area is a heating zone.

In another aspect of the presently described embodiments, the radiation emitting devices of the first array cooling subassembly and the second array cooling subassembly are of the same type.

In another aspect of the presently described embodiments, the radiation emitting devices of the first array cooling subassembly and the second array cooling subassembly are of different types.

In another aspect of the presently described embodiments, the first array cooling subassembly is connected to a first cooling system and the second array cooling subassembly is connected to a second cooling system.

In another aspect of the presently described embodiments, the system further comprises a controller operative to control a flow of fluid to the first array cooling subassembly and the second array cooling subassembly.

In another aspect of the presently described embodiments, the system further comprises at least one of a fluid regulator and a temperature sensor.

In another aspect of the presently described embodiments, a method for providing cooling to an array of semi-conductor based radiation emitting devices disposed on an array cooling subassembly including a mounting substrate to which the array of radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features, a heat exchange body connected to a second surface of the mounting substrate, a heat exchange fluid cavity within the heat exchange body operative to maintain a flow of heat exchange fluid in the heat exchange body, fluid connections provided to an inlet and an outlet of the heat exchange fluid cavity, comprises receiving data at a controller, determining fluid flow parameters for the flow of heat exchange fluid in the heat exchange cavity based on the data, and, controlling the flow to the inlet of the heat exchange cavity based on the determined fluid flow parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a system according to the presently described embodiments;

FIG. 2 is a system according to the presently described embodiments;

FIG. 3 is a system according to the presently described embodiments;

FIG. 4 is a system according to the presently described embodiments;

FIG. 5 is a system according to the presently described embodiments;

FIG. 6 is a system according to the presently described embodiments;

FIG. 7 is a system according to the presently described embodiments; and,

FIG. 8 is a method according to the presently described embodiments.

DETAILED DESCRIPTION

A purpose of the presently described embodiments is to apply a properly sized cooling system to solid state, semi-conductor based electromagnetic irradiation device arrays used in heating and curing applications. One such application involves systems for cooking food. Another application of the presently described embodiments is to systems using narrowband semi-conductor based radiant heating of plastic components, such as PET bottle preforms in a bottle blowing process.

The contemplated cooling system may take a variety of forms including heat transfer fluid systems such as state change cooling systems (including vapor phase (or two phase) cooling systems), water based cooling systems (including systems using water mixtures including, e.g. ethylene glycol), air cooling systems or common refrigerant cooling systems (e.g. systems using chlorofluorocarbons (CFCs), hydro chlorofluorocarbons (HCFCs), butane, or propane).

With reference to FIG. 1, a system 10 includes solid state, semi-conductor array radiation sources 12. The sources 12 can be comprised of any one or combination of a variety of types of devices including laser diodes, solid state lasers, or other types of laser devices, LED's including power LED's, surface emitting devices including surface emitting laser devices, micro-wave semi-conductors, light emitting transistors (LET's) or other electromagnetic or RF producing semi-conductors. These devices or sources are arranged in arrays in at least one form. The arrays may take a variety of suitable configurations; however, in at least one configuration, the arrays are two-dimensional. Still further, the arrays may be configured as X-by-Y arrays, where both X and Y are greater than 1. The arrays may include devices (either within an array or in separate arrays) having center wavelengths separated by at least 150 nanometers. In at least one form, the sources may be semi-conductor irradiation emitting devices emitting energy or irradiation in a narrow band in the infrared, visible or ultraviolet ranges. These narrow bands, for example, may be less than 300 nanometers, full width half max. Also, in at least one form, the radiation sources are narrowband sources wherein the radiation emitted at narrow wavelength bands is selected to enhance the heating/cooking process, as described in, for example, U.S. Pat. No. 7,425,296, U.S. Ser. No. 11/448,630 (filed Jun. 7, 2006), U.S. Ser. No. 12/135,739 (filed Jun. 9, 2008), U.S. Ser. No. 12/718,919 (filed Mar. 5, 2010) and U.S. Ser. No. 12/718,899 (filed Mar. 5, 2010), all of which are incorporated herein by reference in their entirety, and others.

As shown, the sources 12 may be mounted directly to a conductive or heat sink surface, or mounting substrate, 14—with the opposite side directly in contact with a heat exchange body 16. For ease of reference, the sources (or arrays of sources) 12, the conductive surface or mounting substrate 14 and the heat exchange body 16 form an array cooling subassembly 11.

The sources 12 may be connected to the substrate 14 in any of a variety of manners. In one form, the arrays of the sources 12 are soldered to the substrate 14. The substrate 14 may also then be soldered to the heat exchange body. Also, it should be appreciated that the heat exchange body and the mounting substrates (or conductive surfaces) may be separate elements or formed as a homogeneous unit.

The mounting substrate 14 will, in at least one form, be made of material with high thermal conductivity (such as, but not limited to, copper, diamond, nano-conductor composites or alloys thereof, or materials having these components included therein) to reduce the thermal resistance between the temperature sensitive semi-conductor junction and the cooling elements. This substrate may also function as an electrical circuit for the solid state, semi-conductor emitters. In this way, the substrate may include an electrical insulation material (such as a diamond composite or ceramic material) or a heat spreader of suitable material (such as a diamond composite or nanomaterial composite) to improve performance. The substrate may be formed of a single layer or multiple layers to accomplish the above recited functionality. Accordingly, a layer may be provided to provide thermal conductivity and another layer may be provided to provide electrical insulation. Or, a material that is able to provide both features may be used. Also, it should be understood that the mounting substrate may, in some cases, include an electrically conductive layer or circuit board components or materials to facilitate proper circuit or electrical connections (e.g. for the sources). The mounting substrate will be sized to suit its functionality and the environment of its use. However, in one form, the mounting substrate is relatively thin, e.g. having a thickness in the range of hundreds of microns, or having layers wherein each layer has a thickness in the range of hundreds of microns.

As shown, a cooling system 20 is, in one form, located remotely from the arrays to provide for improved, and possibly optimum, management of the removed waste heat. As noted above, the cooling system 20 may take a variety of forms.

With reference now to FIG. 2, another view of the subassembly 11 of system 10 is shown. In this regard, the subassembly 11 includes sources 12, which are shown as being positioned on a first surface of a mounting substrate 14 in an array fashion. The mounting substrate 14 is also connected via a second surface to the heat exchange body 16. The heat exchange body 16 has a heat exchange fluid cavity 15 configured to maintain a flow of heat exchange fluid 19 therein. In this view, the plumbing or fluid connections 17 to the cooling system 20 are also illustrated, although, the cooling system 20 is not illustrated in FIG. 2 for ease of illustration. The fluid connections 17 may take a variety of appropriate forms (e.g. may be formed of a variety of suitable material and have a variety of configurations and features) and are provided to an inlet and an outlet of the heat exchange fluid cavity 15. As noted above, emitters or sources 12 may be attached to the mounting substrate 14 in a variety of manners, including soldering. It should also be appreciated that the emitters 12 may be connected or soldered to electrical traces (not shown) on the mounting substrate 14. Also, as noted above, the mounting substrate 14 may be connected to the heat exchange body 16 in a variety of manners, including soldering. It should be understood that other connection techniques such as deposition (e.g. vapor deposition, sputtering, . . . etc.) or adhesive techniques may also be used.

With reference to FIG. 3, a system 10′ shows that a properly sized cooling system 20′ is distributed across multiple arrays of solid state sources 12′ organized on corresponding mounting substrates or conductive surfaces 14′—which connect to corresponding heat exchange bodies 16′. Two (2) subassemblies 11′ are shown, but the number may vary according to the implementation. It should be appreciated that like numerals (differing only by a prime designation (′)) in FIGS. 3 and 4 generally correspond to like elements of FIGS. 1 and 2.

With reference more specifically to FIG. 4, the system 10′ shows that the multiple subassemblies 11′ are distributed relative to, e.g. around, a work area or cavity 18′ to perform, for example, suitable heating or cooking functions. The work area or cavity 18′ may correspond to a variety of different work environments including oven cavities, heating zones, . . . etc. Also, it should be understood that the number of subassemblies and their orientation relative to the work area may vary. For example, in another form, all subassemblies may be positioned on one side of the work area. The plumbing or fluid connections 17′ connect the subassemblies 11′ to a single heat exchanger or cooling system 20′.

Furthermore, as noted above, the arrays could comprise multiple different types of solid state radiation sources such as those described in connection with FIG. 1 (such as infrared and microwave emitters). With reference to FIG. 5, it will be appreciated that various radiation sources may be packaged in subassemblies such as subassemblies 511 and 513—which, in at least one form, have a configuration which resembles the subassembly 11 of FIG. 2. As shown, subassembly 511 is connected back to the cooling system 520 via plumbing or fluid connection lines 517. In this configuration, the subassembly 511 has sources of a first type TYPE 1 (e.g. infrared sources such as those described above that may emit in a narrow band) positioned thereon in an array. Likewise, subassembly 513 connects to cooling system 521 by way of plumbing or fluid connection line 517. In this configuration, the subassembly 513 has sources of a second type TYPE 2 (e.g. microwave sources such as those described above that emit in the microwave range) positioned thereon in an array. These various radiation sources surround work area or cavity 518 as shown. To clarify, the cooling systems 520 and 521 may take a variety of forms, as described above. Also, the work area 518 generally corresponds to the work area 18′ described above.

In a still further embodiment, the radiation sources 12 or arrays thereof may be arranged in series in the contemplated cooling system. In one form, such a series arrangement is advantageously implemented for vapor phase cooling systems, but has less advantages with other cooling systems where a parallel arrangement (e.g. such as that shown in FIGS. 4 and 5) has more advantages. In this regard, with reference to FIG. 6, a system 610 is shown. The system 610 includes arrays cooling subassemblies 611 that resemble the subassemblies 11 described above and surround a work area or cavity 618 (which corresponds to work cavity 18′ described above). The subassemblies 611 are connected to the heat exchanger or cooling system 620 via plumbing or fluid connections 617. As shown, the fluid connections or plumbing 617 is connected to the device arrays 611 in series fashion—e.g. where the outlet of one subassembly 611 is connected the inlet of a second subassembly 611.

It should also be appreciated that systems according to the presently described embodiments, such as the systems described in connection with FIGS. 1 through 6, may also include feedback features. Such feedback features may provide improved performance, particularly since the loads of different devices are unlikely to be the same. In this regard, the system may be provided with a monitoring system (e.g. temperature sensors, thermo-couples or the like, and a controller) to monitor the heat load of the radiation sources. The monitoring system may then redirect coolant based on the determined load. As an alternative, the monitoring system may redirect the coolant based on a predetermined or known duty cycle.

In this regard, with reference now to FIG. 7, an example system 710 is illustrated. Although the system 710 generally resembles the system of FIG. 4, a feedback system as described may be implemented on any of the systems described in FIGS. 1 through 6. The system 710 includes subassemblies 711 that correspond to the subassemblies 11 described above and surround a work area or cavity 718 (that generally resembles work cavity or area 18′). The subassemblies 711 are connected to the cooling system 720 by way of plumbing or fluid connection 717. Fluid regulators 722 are provided between the respective subassemblies 711 and the heat exchanger 720. Also shown are sensors or thermo-couples 723 positioned, in one example configuration, at the outlet of the subassemblies 711. The sensors or thermo-couples 723 may take a variety of forms. Also, a controller 724 is illustrated as being operatively connected to the cooling system 720 (which, as above, may take a variety of forms). The sensors 723 and the controller 724, in one form, comprise the monitoring system as described above. It should be appreciated that the controller 724 may take a variety of forms, including a substantially dedicated controller for the cooling system or a controller for a heating or cooking system to which the presently described embodiments are applied. The controller may be implemented as hardware such as a computer or processor that executes routines using a variety of software techniques. In this way, methods according to the presently described embodiments (including the example method described in connection with FIG. 8 below), may be implemented using a variety of hardware configurations, including storage media that is computer readable or machine readable (e.g. in a controller 724 using related sensors 723 and fluid regulators 722, and appropriate memory devices and/or locations such as digital, magnetic or optical memories or drives), executing various routines to achieve functionality and/or execute steps or instructions of the methods contemplated by the presently described embodiments.

In operation, with reference now to FIG. 8, an example flowchart for an example method 800 according to the presently described embodiments is shown. As illustrated, the controller 724 receives data (at 802). It should be appreciated that, in one form, the data may be obtained by reading sensors or thermocouples that measures any of a variety of temperature levels such as the temperature of the fluid exiting the subassemblies 711, the temperature of the heat exchange body, and/or the temperatures of the arrays of sources. It should be appreciated that, in some cases, the sensors may not be required where prior knowledge of the heating or duty cycles may be used to regulate fluid flow. Such knowledge may also be used in conjunction with the data obtained by sensors to provide enhanced performance.

In any case, the controller 724 uses the data available to it to determine fluid flow parameters (at 804). In at least one form, the fluid flow parameters include an amount of fluid that should be fed to the subassemblies 711 and/or a rate of flow of such fluid. These parameters may be calculated using a variety of techniques including using look-up tables or executing routines to calculate such parameters. The form of the tables and the routine and/or the calculation will vary from application to application.

Once the parameters are determined, the controller 724 then sends signals to the fluid regulators 722 to control an amount or rate of fluid that is fed through the plumbing 717 to the sub-portions 711 (at 806). Such control of the fluid regulators may be accomplished using a variety of techniques, including through the cooling system or by way of more direct electronic control (e.g. wired or wireless) from the controller.

The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. 

1. A system for providing cooling to an array of semi-conductor based radiation emitting devices, the system comprising: a mounting substrate to which the array of radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features; a heat exchange body connected to a second surface of the mounting substrate; heat exchange fluid cavity within the heat exchange body operative to maintain a flow of heat exchange fluid in the heat exchange body; and, fluid connections provided to an inlet and an outlet of the heat exchange fluid cavity.
 2. The system as set forth in claim 1 further comprising a cooling system connected to the fluid connections.
 3. The system as set forth in claim 2 wherein the cooling system is at least one of a vapor phase cooling system, water-based cooling system, air based cooling system or refrigerant-based cooling system.
 4. The system as set forth in claim 1 wherein the semi-conductor based radiation emitting devices emit energy in narrow band in one of the infrared, ultraviolet and visible ranges.
 5. The system as set forth in claim 3 wherein the narrow band is less than 300 nm, full width half max.
 6. The system as set forth in claim 1 wherein the semi-conductor based radiation emitting devices emit energy in the microwave range.
 7. The system as set forth in claim 1 wherein the mounting substrate is formed of or contains at least one of copper material, diamond material, nano-conductor composite material or alloys thereof.
 8. The system as set forth in claim 1 wherein the mounting substrate and the heat exchange body are integral.
 9. The system as set forth in claim 1 further comprising a controller operative to control a flow of fluid to the heat exchange fluid cavity.
 10. The system as set forth in claim 1 further comprising at least one of a fluid regulator and a temperature sensor.
 11. The system as set forth in claim 1 wherein the array is two-dimensional.
 12. The system as set forth in claim 1 wherein the array is an X-by-Y array wherein both X and Y are greater than
 1. 13. A system for providing cooling to multiple arrays of semi-conductor based radiation emitting devices, the system comprising: a first array cooling subassembly including a first mounting substrate to which a first array of radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features, a first heat exchange body connected to a second surface of the mounting substrate, a first heat exchange fluid cavity within the first heat exchange body operative to maintain a flow of heat exchange fluid in the first heat exchange body, and first fluid connections provided to an inlet and an outlet of the first heat exchange fluid cavity; and, a second array cooling subassembly including a second mounting substrate to which a second array of radiation emitting devices is mounted on a first surface thereof, a second heat exchange body connected to a second surface of the mounting substrate, a second heat exchange fluid cavity within the second heat exchange body operative to maintain a flow of heat exchange fluid in the second heat exchange body, and second fluid connections provided to an inlet and an outlet of the second heat exchange fluid cavity.
 14. The system as set forth in claim 13 further comprising a cooling system connected to the first array cooling subassembly and the second array cooling subassembly.
 15. The system as set forth in claim 14 wherein the first array cooling subassembly and the second array cooling subassembly are connected in parallel to the cooling system.
 16. The system as set forth in claim 14 wherein the first array cooling subassembly and the second array cooling subassembly are connected in series with the cooling system.
 17. The system as set forth in claim 13 wherein the first array cooling subassembly and the second array cooling subassembly are arranged relative to a work area to perform heating and cooking functions.
 18. The system as set forth in claim 17 wherein the work area is an oven cavity.
 19. The system as set forth in claim 17 wherein the work area is a heating zone.
 20. The system as set forth in claim 13 wherein radiation emitting devices of the first array cooling subassembly and the second array cooling subassembly are of the same type.
 21. The system as set forth in claim 13 wherein radiation emitting devices of the first array cooling subassembly and the second array cooling subassembly are of different types.
 22. The system as set forth in claim 21 wherein the first array cooling subassembly is connected to a first cooling system and the second array cooling subassembly is connected to a second cooling system.
 23. The system as set forth in claim 13 further comprising a controller operative to control a flow of fluid to the first array cooling subassembly and the second array cooling subassembly.
 24. The system as set forth in claim 13 further comprising at least one of a fluid regulator and a temperature sensor.
 25. A method for providing cooling to an array of semi-conductor based radiation emitting devices disposed on an array cooling subassembly including a mounting substrate to which the array of radiation emitting devices is mounted on a first surface thereof, the mounting substrate including at least one of a first material having high thermal conductivity and a second material having electrical insulating features, a heat exchange body connected to a second surface of the mounting substrate, a heat exchange fluid cavity within the heat exchange body operative to maintain a flow of heat exchange fluid in the heat exchange body, fluid connections provided to an inlet and an outlet of the heat exchange fluid cavity, the method comprising: receiving data at a controller; determining fluid flow parameters for the flow of heat exchange fluid in the heat exchange cavity based on the data; and, controlling the flow to the inlet of the heat exchange cavity based on the determined fluid flow parameters. 